Originally Posted by Guess
led's used for the backlight have a lifespan of 50-100,000 hours. Either way.. at 50,000 hours.. .the backlight will last 5.7 years of being constantly on before it would give out.
Most LED's fade away rather than suddenly giving out. LED's of the typical intensity now used in cellphone backlighting, will potentially last well over 100,000 hours, but at diminished intensity.
LED's driven at dim levels in a bedroom at 10% backlight intensity, will probably last 500,000 - 1,000,000 hours or more, since the Bold uses PWM-driven backlighting. (pulse width modulation), which means for dim backlight at 10%, it's 90% off and 10% on. PWM used for LED dimming, typically greatly prolongs LED life... Under-driven white LED's have amazingly long life.
The hours of lifetime you see quoted for LED's are typically at their full rated power. This is true if your Bold was outdoors in the sun, not at bedside -- at that bedside mode intensity, it would probably last 50 years running 24/7.
Power LED's that generate lots of heat, such as 1-watt, 3-watt or 5-watt Luxeon's or Cree's, does have very significantly shortened lives if not properly cooled...
As for LCD burn-in (yes it exists, but reversible
) (Apple LCD monitor burn in
), LCD's normally do not burn in but the crystals have a reversible memory effect in some cheap LCD's. A few crystals get stuck sometimes when they're displaying the same image for a long time, then the image changes, but they eventually unstick themselves. Often, it takes a few hours to completely erase a LCD burn in some cheap LCD displays. However, cellphone displays, are normally immune to this effect, especially when driven properly with proper inversion
. A few exceptions exist (like the Nokia display) but they are exception to the rule. LCD can be made immune to the burn-in effect though -- old BlackBerries (i.e. 7280) have displayed the clock for YEARs as their screens do not turn off, but the backlight does -- and there is no burn-in on these old BlackBerries.